Conveying structure.



' A. E. NORRIS;

CONVEYING smucruae. I APPLICATION FILED MAY 3 I916.

Patented Apr. 1,1919.

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N fi cvenior Almon llNorr-is Patented Apr. 1,1919.

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Inventor.

IZNorr 1 A. E. NORRIS. cnuviyms smucrune.

APPLICATION FILED MAY 3. l9l6.

fllmon 33% A. E. NORRIS. CONVEYING STRUCTURE.

z APPLICATION map mus. 191s. 1 1,299,010. Patented A111. 1,1919.

8 SHEETS-SHEET 3.

, .Zitvezzior Almon E.Norris A. E. NORRIS.

CONVEYING STRUCTURE.

APPLICATION msp MAY 3.19:5.

1,299,010. N Patented Apr. 1,1919.

B SHEETS-SHIET 4.

A. E. NORRIS.-

CONVEYING STRUCTURE;

APPLICATION FILED MAY 3 IBIS.

Patented Apr. 1, 19194 a SHEETSSHEET 5,

Almon ENorria fiavenior 'A. auoams. V CONVEYINGSTRUCTURE. M'RLICQTION FILED MAY3. l9l6.

Patented A ,1919;

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E. NOR RTS.

CONVEYING STRUCTURE.

APPLICATION FILED MAY3. I916,

Patented A i. 1,1919

8 sucnswmus.

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n TED STATES PATENT oF Ion.

I ALMON E. NORRIS, F CAMFRIDGE, MASSACHUSETTS.

CONVEYING STRUCTURE.

Lasagna.

Application filed May 3, 1916. Serial No. 95,241.

To all whom it may concern:

Be it known that I, ALMoN E. NORRIS, a citizen of the United States, and a resident of Cambridge, county of Middlesex, State of Massachusetts, (whose post-office address is 31 Main street, Cambridgeport, Massa chusetts,) have invented an Improvement in Conveying Structures, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to conveying structures which are adapted to travel along,

rails and transport hoisting or other apparatus mounted thereon to different points.

, Among other objects the invention pro-, vides strong and effective means for holdlng the structure securely to the rails and means for controlling the application of the holding means to and the release of the same from the-rails. The invention is an improvement upon the construction shown in my 00- pending application Serial No. 872,029 filed November 13, 1914..

The'character of the invention may be best understood by reference to the following description of an illustrative embodiment there of shown n the accompanyingdrawings,

wherein Figure 1 1s a plan of a conveying struc- 'ture shown herein as equipped with rail clamping means and controlling means therefor; Fig. 2 is an end elevation of shown in Fig. 1; v

. Fig. .3 is a side elevation'o'f the structure shown in Fig. 1;

Fig. 4 on an enlarged scale is aside elevation of the railclamping means;

the structure Fig. 5 is a vertical section taken on line" of Fig. 4;

Fig. 6 is a section similar to Fig. 5 showing the parts in a different position; v

- Fig. 7 is a horizontalsection taken on line 74 of- Fig. 5;

Fig. 8 is a plan of a .frame carrying a winding drum for controlling the rail clamps. the motor for driving said drum. and

a brake for said motor and controlling devices therefor;

. i 1 Fig. 9 IS a side elevation oi the mechanism shown 11: Fig. 8;

Specification of Letters Patent.

-' Fig. let is a view similar to .Fig. 18 show ing the partsin' a different position;

Fig. 15 1s a vertical section through the switch device shown in Figs. 13 andl i;

Fig. 16 is a.horizontal section taken. on

line 16-46 of Fig. 14;

Fig. 17 is a vertical section taken on line 17-47-01 Fig. 13; I I

F ig. 18 on an enlarged scale is a view partly in plan and horizontal section of the I system of levers for controlling the brake;

Fig. 19 is a side elevation of the system of levers. shown in Fig. 18;

Fig. 20 is a side elevation of the electrical controller; I

Fig. 21'is a plan of said controller;

Fig. 22 is a diagrammatic view including a development of the drum. contact segments and devices, and electrical connections cooperating therewith;

Fig. 23 is a view partly in horizontal section and partly in plan showing the clamp cam and its shoe; and

Fig. 24 is a verticalsection taken on line -24-24 at Fig. 23.

Referring to the drawings, the illustrative apparatus shown therein asembodving the invention comprises a conveying bridge stru ture 1 (Figs. 1, 2 and 3) mounted on trucks 3 having wheels 5 on shafts iournaled in bearings therein. As shown herein each truck is provided with four wheels and each truck is provided with a motor 7 for driving said wheels. the motors being controlled as more fully hereinafterdescribed. a

Each truck may be equipped with means for clamping the same to the raii along which it travels. Since all of the clamps are similar in construction, a description of one will sufiice for all. The illustrativeclarnp shown herein as embodying the invention comprises opposed jaws adapted to' grip the rail between them. These jaws embody certain features of the jaws describedin said co-pending application. The inner jaw is in the form of a cam 9 (Figs. 5, 6 and 23)- [having a vertical end groove fulcr'umed on a pin -13 mounted in a segmental shaped housing 15. j I Y 4 The cam maybe provided with a shoe 9", having a fiat surface to engage the rail. A tooth 9} on the shoe is adapted to enter a recess in the outer end of the cam to cause the 10 shoe to move along the rail with said cam. A flange 9on the shoe overlies the outer edge of the'cam, supports the s'hoe'thereon', and prevents entrance of snow or other foreign matter between the opposed faces of said cam and shoe. End flanges 9 contribute to the protection of said faces. The cam has a central flat ortion fornormally pressing said shoe against the rail and curved portions of longer radius. If the structure tends to travel along the rails the cam 9 actmg as an automatic gripping means will rock on its pin 13 and one or the'other of fthese longer radius portions will press against the shoe and increase its grip on'the fall. i i :The use of the shoe provides a renewable wear part between the cam aiidthejrail preventing the end of the cam from sliding contact with the rail. This distributes the .39 Wear over a substantially flat surface in-"I stead of localizing it on the curved faces of I the cam, thus iiot only lessening the wear i but taking it oil from those surfaces the precise configuration of which should prefera'bly be maintained. To normally maintain the cam in'a central; position it is provided with springsl? (Fig. 12) encircling bolts,19contained in casings 21 diverging from said segmental 4 housing 15.

' The segmental housing 15 maybe integral with an upright arm 23 .(Figs. 5 and 6) hav-'- ing a ioot 25 projecting over and resting upon the rail and adapted to slide along the at seine-and support-the arm 23 and the cam member'9. H I To press the cam member against the rail at the times desired a second arm 27 may be provided opposed to the arm 23 and having -.a portion provided with a shoe 29 adapted for engagement with a side of the rail-opposite to'the cam member 9. T j The jaw arms 23 and 27may be mounted "between end walls 31 of a housing 33 which may bebolted on anend of the truck asv well shown in Fig. 4. This housing provides a A strong and rigid'connection with the truck enabling the jaws; when grippedtothe rail to present an end thrust against the walls of .60 the easing and effectively 'resistfthe travel of thetruck along the rails. The walls 31 maybe strengthenedby a tie bolt 34 proj ecting' through external bosses on said "w ll i,. Q. as The-jaw arm 23 may be connected by a.

35 5 and 6) witha .fixed pivot pin 37 extending between and'securedto v the endwall's- 31 of the casing. The aws may be pivotally connected by a series of links39(Fig. 12 )entered into opposed recesses in said aw arms and connected thereto by through pins 41. i

fWhen'the upper end of the jaw arm27 is rockedaw-ay from the railor in a contraclockwise direction (Fig. 5) it will first swing about the pin41 and press its shoe against the outer face of the 'rail, after f 'which further rocking of the jawjarm will H act through the links 39 to draw .its com panion' jaw 23" toward theopposite face of 8.0 the rail and securethe truck to said'rail.

Next will be described'means for rocking the jaw arm 27 toapply or releasethe clamp as desired. To accomplish this the upper ends of. the jawarms are connected to the outer ends of toggle links 42,. their meeting I ends being connected to a pin 43 having a jointed connection with an upwardly extending rod44. The'upp'er end of this rod has a jointed connection with an arm 45 (Fig. 4)pfast on a shaft 47 journaled n bearings in brackets 49 projecting upward 'from they casing 33 referred to. An arm 51 may be also mounted fast on said shaft and carry a heavy weight .53 which may be held 9 at different distances on said arm from. Said shaft by an'adjustable bolt 55. l

' -When the weight arm is rocked down to its position. shown in full lines in Fig. 4,:it will thrustthe rod downward, .thereby straightening the toggle links 42 and rocking the jaw arm 27 in acontra-clockwise direction from its released position shown in'Figr 6 to its applied position, shown in Fig. 5. t

Itwill thusbe seen that in addition to the jointed connectionot the upper ends of the i jaw arms to thef toggle' links 42, the lower end of the jaw-arm 27 is pivoted to the links 29 while the jaw arm 23. at its upper endis jointed to the frame through the link 35 and its lower end is loosely.supported by the rail through the shoe25.

In order that the 'jaw 27 may be susceptible of a slight movement to compensate for vai'iations in the width of the, head of the rail, preferably its toggle link is not connected to impart a positive thrust theretobut is connected thereto by a pin'57 in an elongated slot. 59 in an ear 61 projecting from said jaw arm. I The pin 57 is normally pressed to the inner end of the elongated slot bv-theengagement of the free end of jaw armmay move more or less relatively to its 'linkto meet the condition referred to, it being understood that the spring 63 is of greater stifi'ness than the springs 1'?" 130 '20 cables 69 there are provided cables 71 and 73 referred to and able toapply apowerful holding pressure to the jaw ofv said arm.

' controlling the applying andreleasing of the rail clamps. To accomplish this each clamp is provided with an arm 64 (Fig. 1) fast on its-shaft i7 and connected by a shackle 65 and turn buckle 67 with a cable 69 or other suitable flexible connection.

Referring now to Figs. 1, 2 and 3, to haul. in or let out the several clamp-operating which lead from the rail "clamps at the front plerupward to guide sheaves and thence horizontally. rearward about guide sheaves 77 (Fig. 1) to: a common cable .79. This 'at-the rear pier are connected to cables 88.

and 89 which extend upward about guide sheaves 91 and 93 to guide sheaves 95 and are'connect-ed to a common cable 97. 'This cable is guidedhy sheaves 99 and 101 and is anchored to the winding drum 85. The common cables 79 and 97 are connected to said drum so that when the latter is rotated in'one direction it will draw the cables upward to'release the clamps for all of the trucks and when said winding drumv is 3Y0- tated in theopposite direction it -will pay out the cables and permit the weighted arms of the clamps to'apply the same. i

Referring now more particularly "to Figs. 8 and 9 the winding drum is mounted fast on a shaft 84 journaled in bearings in a. frame 86. This shaft has a gear fast thereon drivenby a pinion 92 fast on a shaft 3 9 1 journaled in bearings in' said frame, saidshaft also carrying a gear 96 driven'by-a inion 98 fast on a-shaft 100 jonrnaled in earings in said frame." This shaft projects beyond one side of said frame and hasa gear 103 fast thereon driven by a pinion 105 on the shaft of an electric motor 107.

hen the motoris driven in one direction it will operate through the transmission described and drive the winding drum 85 thereby drawing upward the cables connected to the clamp controlling levers and thereby releasing the chnnps. When the winding drum is permitted to rotate in the opposite direction'it will allow the clamp weights .53 to drop downward and apply. the clamps as described. The motor shaft is provided with a brake wheel 109 (Fig. 8)

fast thereon having a strap 111 cooperating therewith. One end of said strap is an .3

chored by a bolt 113 to a plate 114 fixed to the side of theframe 86 and theopposite end is connected to brake-controlling ni'eans about to be described. This brake-controlling means constitutes an important feature of the invention and has provision for automati: ally applying the brake-to arrest the drum when it has drawn the clamp-releasing cable upward a sufficient extent to release the clamps; to arrest the drum when it lies "unwound the cable sufficiently to apply the clamp; to retard theunwinding rotation of the drum and prevent the cables froni' paying out too rapidly in: allowing the downward rocking of the weighted levers in applying the clamps and to prevent toot rapid a movement of the drum in either direction. This brake-controlling means comprises a lever 115 (Figs. 8. '9, 18 and 19) having one end connected to the brake strap 111 and its opposite end pivotally connected by a short link 117 with a floating lever 119.

The lever 115 is pivoted intermediate its ends on a pin 121 at one end of two bars constituting a main lever 123. pin 125 at the oppositeend of these bars is connected with an ar'm127 fast on a shaft 129' journaled in hearings in brackets 131 on the frame 86. Arms 132 also fast on saidshaft carry a wheel 133 of a width substantially equal to: the width of the drum and adapted for engagement with the cables leading from said drum. T hese arms constitute a bell crank which is normally rocked in a clockwise direction (Fig '19) to press said wheel against said cables by a coil spring 135 ha ving oneend; connected to the arm 127 audits opposite end anchored to a bracket 137; on the frame. The main lever 123 is connected by links 139 withfa fixed the cables. 'In so doing, it will rpck the main lever 123 in a contra-clockwise direction (Fig. 19) about its point of pivotal connection with the link 139 and thereby rock the lever 115 in a similar direction about its point of pivotal connection with the link 117. This will tighten the brake strap to the brake wheel and retard the unwinding of the cables from the drum. As the cables are made taut the bell crank 127 will rock back toward its. original position and automatically release the brake. Thus the. proper tension for the cables will be auto mat1cally maintained. When a sufiicient length ofcable has unwound to apply the the frame. 18 connected to one end- &

clamps, the table will remain slack and the bell crank will remain in position to 'hold the brake applied. I One end of the floating lever 119 is connected by a'sha'ckl'e 14:3](Fig 11 )"with the curved'arm of a bell crank 145 fulcrumed at 146 on a bracket 147 projecting from The other arm of the'bell crank 149 the opposite end of to a bracket '151 projecting upward from the frame.

The bell crank is ada ted to be rocked in a clockwise direction nor comprising ahead 153 secured to an end ig. 11) by a goverof the transmission shaft 100 referred to actof a coil spring. which is anchored.

ing in conjunction with semi-sphericalgdvernor weights 1.55 and 156 mounted on arms 157 pivotally connected at 158to said head.

Pins 159- project from said arms intoelongated slots in cars of a collar161, said collar being mounted on the reduced end of aspindle 163 projectingfrom a bore insaidhead outward between the governor weights and having a head 165 seated'in a cup-shaped bearing 167 in the bell crank arin.--- I .When the winding drum attains a sufficient. speed of rotation, it ,will cause the governor weights to separate or fly outward vices are employed.

solenoid-actuated movement of the plunger 175 acts to rock the floating lever about,

this pin asa fulcrum and through the short link 117 will rock the lever 115 about the pin 121 in a contra-clockwise direction, thereby tightening'the brake strap to the brake wheel and causing the arrest of the motor.

To cause'the brake-applying solenoid to be energized, as soon as the clamp-releasing motor is stopped and to permit the clamp-releasi11g motor to be actuated only when the brake-applying esolenoid is de-. energized, suitable automaticlswitching de- To actuatesuch switching devices there is employed 'a sprocket wheel 183 (Fig. 8) mounted on one end of. the drum shaft 84 and connected by, a sprocket chain 185' with a larger sprocket wheel 1'87 fast on a shaft 189 journaled in bearin s in 10' and 13 to 17 on the frame. throughsaid casing and on the opposite "a casing 191 (Figs. 9,

'side' thereof is provided with an arm 195 by centrifugalforce and shift thefcollar' 161 to the right. of Fig. 11 thereby'in turn shifting the spindle 163 to the right and swingingthe bell crank in a clockwise dilever119 to which it is motion against the resistance of its sprin x149. This will cause the shackle 143' to pull upward on the'end of the floating it the link 117. This will draw the lever 123 up against a fixed stop 168"-;(Fig. 9) on the frame and rock the lever "115 in a contra-clockwise direction on its pin 121, thereby tightening the brake strap on. its wheel with a force varying according to the speed'of rotation of the drum. Thus, the. governor will serve .automatically'to prevent an over rapid downward rocking of the weighted levers in applying the outward from the frame so that the clamp.

The opposite end of the floating lever 119 is pivotally connected to a rod 169 (Fig.

19) adjustably connected by a turn .buckle- 171 with a rod 173 pivotally connected to the plunger 175 of a solenoid 177 mounted on a bracket 179 (Fig. 10) on the frame. This solenoid when energized as more fully, hereinafter described will pull its plunger upward and thereby lift the end of the floating lever 119 to which it is. attached.- The. end of the floating lever which. isconnected to the governor, is normallyheld by the sprii1g-drawn bell-crank 1 15 down against a stop pin 181 (Fig. 11) prof'ecting rther connected. and with fast thereon. l

A shaft 197 is journaled in' bearings centrally of said. casing. and has a switch 199 fast thereon within the casing which switch controls the circuits for the clamp.-releasing motor and vthe brake-controlling sole- .noid. When this switch is in the position shown in Fig. 15 it connects a spring finger g v201 mounted on a bracket wltha spring finger 205 mounted on a bracket 207 in the casing, the fingers 201 and 205 being located in the brake solenoid circuit. as will more fully appear from the description of the controlling; circuits which followsz When the switch is rotated through an arc of 90 it will break connection with the spring fingers 201 and 205 and interrupt the circuit for the brakea-pplying solenoid and connect a springcontactfinger 209; on a bracket 211 in the casing with a spring-contact finger 213 on 203 in the casing,

mounted on a bracket193 The shaft 189 projects a bracket 215 in the casing, the fingers 209 and 213' being in the circuit of the clampreleasing motor. I To shift the switch as described the shaft carrying the same may be provided with a lever 217 having a toe 219: adapted to be- 221 provided with an downward movement' 'of that endf the" floating lever prevented and the Il -"ward- :lclockw-ise direction until ina.

- to trip the dog as 'morefiilly, hereinafter V The lever 217 referred to has It may be. assumed the arm 195 is inits position shown in dotted lines in Fig. 13'

when the clamp operatin weight arms are in position to apply the c amps to the rails, and that it is desired to releaseythe clamps.

To acomplish this the motor is started, there by rotating the winding drum and causing the clamp releasing cables to be wound thereon. During this winding movement of the drum the sprocket wheel 183, chain 185,

2 and sprocket wheel'187 will impart rotation,

but at a slower speed, to the shaft 189. This will cause thearin 195 to travelfromits position shown in dotted lines (Fig. 13) in a clockwise direction until it reaches the dog finger 235. As the arm 195 continues to move it rocks the dog in a contra-clockwise direction against the resistance of its spring 231 and trips the dog from the lug 223 on the heel of the lever 217. This renders the 0 spring 239 efi'ective to'cause the lever 217 to fly around in a contra-clockwise. direction! until limited by the engagement of its lug 223 with the stop 241. This will shift the switch 199 with a sharp, quick movement.

3 from its position shown in dotted lines in Fig. 13 to its position shown in full lines in Fig. 15 and break the circuit to" theinotor -and"complete a circuit to be des'bribe When the 'drum' unwinds the cable to ep- 40 ply the clamps, it will cause the arm 195 to rotate in a contra-clockwise direction fromthere is provided a stationary contact 267 its dotted to. its full-line position (Fig. 13,) and thereby reset the-lever 217 in readiness for the next clamp-a plying operation.

4 5 Next will be descri ed a controller and circuits for the motors for propelling the bridgesnpporting trucks, for the brakes for said motors, for-the motor for controlling the latter motor. This controller comprises a drum 243 (Fig. 20). mounted on a shaft 245 iournaled in hearings in a casing 247. The upper end of said shaft has a handle 249 fast thereonprovided with an index 251 movable. over a dial plate 253 havin the diflerent "controller positions marke thereon.

The circuit controlled by the drum comprises a main positive line P (Fig. 22) con- 60 nected by a switch 255 with av conductor a leading to a blow-out coil 257.ronneoted in turn by a conductor a with a stationary contact 259 adjacent the drum. When the drum is shifted to the left of Fig. 22 for 6 forward driving, the stationary contact 259 -motor, thereby causing rotated the rail clamp cables, and for the brake for is connected with a stationary contact 260 by ,a series of "contact segments'261 and a shortcontact segment 262 on the drum. The stationary contact 260 is connected b a conductor at through a switch .266 wit a. fuse 263, connected 'with a. self-starter 264, the latter being connected by a conductor a. with the s ring finger contact 209 referred ;.*-l.o adapte to be connected by the switch 199 wlththe spring finger contact 213. This contact is connectedb a conductor a with the armature and fiel of the clam release motor 107 referred to. This moto is con-i nected to a conductor a? leadin to a switch 265 for connecting the same with the main negative line N. i j When the controller drum is shifted to the left sufliciently to bring the contact segments 261 and262 in position to connectthe stationary contacts 259 and 260, the circuit w'll 'be completed to the clamp releasing the same to rotate 1 the winding drum, pul upthe clamp-releasing cables and thereby'release the clam s. W'hen thewinding drumhas'rotated su ciently to release the clamps the switchactuating arm 195 referred to will have been v y its sprocket and chain connec-.' tions with the winding drum shaft, sufficiently to trip the dog 225. This will cause 4J5 -the switch 199 to snap from its position shown in dottedlines in Fig. 18 to its position shown in full lines in Fig. 15. In the course of this movement; it automatically breaks the circuit to the clamp-releasing motor.

The solenoid 177 should be energized to apply the clam motor brake on the interruption of the rum actuating motor circuit, ,to holdthe clamp-applying weights up in releasing position. To accomplished this,

to the conductor a referred to, and thence 1 to the main negative line. When the switch 199 was shifted to break the motor circuit it completedthe circuit just described tothe solenoid, thereby energizing-the latter and applying the brake. ,120

To start the truck motors 7 for producing the travel of the bridge after'rclease of the rail clamps a conductor 0 is tapped from the conductor 5) referred to, and is connect edto a n'iagn'et 269, cr'mnected in turn by a 5 conductor 0' with the conductor a leading to the main negative line. 'When the switch 199 is shifted. as described it will complete the circuit to and energize the magnet 269. This magnet is used'to close a switch 271 in 139 the circuit to the bridge propelling motors. resistance being connected by a conductor with the amiature 275 of -a typical truck j motor 7. This armature is connected by a to start themotor, the short contact segment conductor'd ;;with--a stationarycontact 277-303 will engagelthe'stationary contact 301,

- a series of resistances 27 3 to theswiteh. 271,

This circuit comprisesa conductor (1 leade with a stationa contact 301 adapted to ing from the conductor 6 referred to through be connected to a s ort contact segment 303, on th drum, said segment being connected by a conductor e withthe contact segment 2 v the .latterbeing connected by a conductor d 9 referred to: When the drum is shifted adjacent the drum; When the drum; is thereby completing the circiiit through the.

" conductor d, with a stationary contact 287; 1 and .willcause the motor to act as a brake-and' shifted sufiiciently-tothe left, this stationary shunt resistance 299. If the wind causes the contact is connected bycontact segments 27%) bridge to travel at a speed substantially and 281m the drum with a stationary congreater thanthat called for by the connectact 283'. The latter is connected by a? con tions Jefi'ected'in that position ofthe con-' ductor d with the field 285 of'thetruck mo troller, the counter electrwmotive force set tor-7,. said fieldbeing connected in turn by a up will producea current in the shunt coil This contact is adapted to be connected by tend to prevent such excess speed. connected contact segments 289 and 291 on By the controller described it is impossible the drum with ajs'tationary'c'ontact 293. 130 startthe truck motors prior to. the re:

This contact is connected by a conductor d leaseoftheclamp'motor, since the circuit to' with a coil 295 forthe brake (not shown) of the truck motors cannot be completed until 35 a truck motor; .This coil is connected by a the clampshave been-completely released,

I onductor d to the conductor a leading to since the switc 199 in the truck motor cir the main negative line. i r cuit is not shif eduntil the clamp motor has When the switch 199 is shifted to break the clampmotor circuit as stated, the magnet clamps. If the controller is shifted to move 269 is energized, thereby a'utoniatically closthe shortcontact segment 262abeyond its ing the switch 271 in the circuit for the fiked contact 260 before the clamp motor hasrotatedsufliciently completely to release'the l Qk t IK' This circuit, however, is not had time to release the clamps, the circuit yetcompletesince the'connected' contactsegto said motor will be broken and the drum ments 279, 281 and the connected contact will pay out t c s. and. vpermit the segments 289, 291 in said circuit-arelocated weights toreapply the clamps. on the controller drum slightly back from -Aftr the bridge has been propelledthe the contact segments 261, 262 on said drum. desired distance, tliecontroller handle may Consequently it is necessary to shift the be turnedt hl the'dlllm back to ts ig drum somewhat farther to, the left of Fig. 22 nal position to break the connection of the 106 to cause said segments 27 9, 281 and 289, 291' Contact segments thereon with the stationary which they coiiperate. ,When the drum is ing motors, apply their brakes, deenergize' soshifted the truck motor circuit described the. solenoid; for the clamp motor brake to will be completed and the brakes will be release the same and permit the drum to released and the motors will start? and propay out-the cables, andthe weights to apply a to contact with the stationary contacts withicontacts. This will arrestthe bridge-conveypel the bridge along the rails. As theidrum 'the.'clam s to secure the -trucks to the rails.

The re 'ation .of the winding drum in paythe series of contact segments 261, referred ing out :tl1e cables resets the switch actuatto, progressively into lengagement with a f ing arm 219'and shifts 'the switch 199 to its 110 series of stationary contacts 297 connected position hown in Fig." '13, where it is in with the resistances" 273 referred to, and readiness to complete the circuit ,to the clam thereby progressively cut out said resistances release motor the'next time the controller andincrease the s'peed of the truck motor.' drumxis shifted to cause the contact seg- When it is desired'to reverse the direction ments 261 to connect .the stationary con-.115

of movement'of the. bridge the controller 'tacts 1259 and 260 in the clam-p' motor cirdrum is shifted to theright, thereby coin cuit. I

v tor. To accomplish this a conductore may ments slightly back' of the 101m release a pleting the circuits as described through condescribed. e

tact segmentspn the drum similar to those clamps immediately on the' arrest of the Means may be provided for'automatic'ally ping it maybe necessary to restart the truck It is not always desirable to apply the l {g truckmoto'rs, since immediately after Stop preventing the wind fromcauSing the'brid motors tosadvan'ce the bridge' somewhat in structure to drift at aspged substantially in orderhto' accurately locate the same: By

excess of the starting speed of the truclz mopositioning the truck inotori contact segbe tapped from the conductor J referred'to 7. contact: segnicntson the drum, t e latter and be connected with a resistance299 in can be turned?to' tlie' right sufficiently 1 0 shuntacross the armatureofthe motor, said" terruptthetruekimotor cirtuit'withoutvingi terrupting the circuit to the brake for holding the rail clamps released; Thus the drum can be turned at once back to the left to complete the circuit to and restart the truck motors without the necessity of applying and releasing the clamps in the meantime.

If the controller'drum is shifted sutliciently to the left to cause both the contact segments'u'of the Jclamp release motor ci rcuitand'the contact segments of the truck n1otor.c-ircuit to engage thestationary con-' tacts which cooperate therewith, it will be unnecessary to further shift the drum to complete the truck motor circuit after shift-i ing the same to complete the clamp release motor circuit, but said truck motor circuit will be completed automatically on the clos ing of the switch 271 in its circu t as described. 1

.Thecontroller described may be located on the bridgewhere conveniently accessible for controlling the travel and arrest thereof. The term clamp herein is used in a broad, generic sense and is to be understood to include any means for securing the con veying structure to the rail.

aving described one illustrative embodiment of the invention without limitin the same thereto, what I claim as new-an "desire to secure by Letters Patent is 1. The combination with a rail clamp of controlling means therefor including a weighted arm, a drum, a cable connecting after said cable has een wound on said said' arm and drum, ;a motorfor rotating said drum to take up said cable and release said clamp, a brake for said drum means for autom'aticall applying said brake drum sufficiently to release said clamp. 2. The combination with a rail clamp of controlling means thereforincluding a weighted-lever, a drum, a cable connecting k said lever and drum, a brake, and means for automatically applying said brake to retard the paying out of said cable in applying, said clamp.

3. The combination with-a rail clamp of controlling means therefor including" a weight for applying said clamp, a drum, 'a

cable connecting said. weight and drum, a

brake, and means for automatically apply- 111%1 said brake to arrest said drum when a su cient length of cable has been, unwound from said drum to apply said clam F 4. The combination with a rail cliimp of controlling means therefor including a weight for applying said clamp, a drum, a

, cable connectmg said Weight and drum, a

motor for rotatingl said drum, a brake, means for automatically applyin said brake to arrest said drum when sai cable has been taken up sufliciently to release said clamp, speed-responsive mea'hs for apply ng said brake to retard the unwinding of and" - to said brake and ment on one arm thereof, a to'theother arm thereof, a

brake to limit the unwinding speed of said drum, and means-automatically to apply said brake after said'drum has rotated sui ficientlyto apply said clamp.

G. The combination with a rail clam'p cif controlling means therefor including a cable,

a winding drum, a motor for said drum, a

brake, a system of levers connected to said brake, and means cooperating with sa d.

levers for automatically applying said brake 1 to limit the winding of said cab e to release said clamp and to automatically check'the unwinding of said cable in applyirlg said clamp,

- 7. The combination with a rail clamp of controlling means therefor including a cable,v

a windingdrum, a motorfon said drum, a brake, means for automatically applying:

said brake to arrest said drum when said" cable has been taken up sufficiently to'rele'ase said clamp, and means automatically to ap ply said brake to arrest said drum when a sufiicient length of cable has beeii unwound therefrom to apply said clamp; I

8. The combination with a. rail clamp ct controlling means therefor including a cable; a winding drum, a motor'for said drum. a brake, and means for actuatin said brake including a mainlever, a bra e lever iful crumed on said main lever,'a floating lewr pivotally connected to said brake lever, speedre'sponsivc means connected toone end of said floating lever and electro-magnetic means connected with the opposite era of said fl ating lever.

9. T e combination with a rai'l clamp oi controlling means therefor including a cable,

a winding drum, a motor for said drum, a brake, a mam lever a brake lever-"connected iulcrumed on said main lever,- a floating lever pivotally' connected 7 intermediate its ends to said brake lever, a governor connected to one "end of said float 'ing lever, and an electro-r'nagnet connected. to the opposite end of said floating-lever.-

10. The combination with a rail clamp of control; in'gmeans thepefor including a cable,

a winding drum, a motor for said drum, a brake, and means .for actuating said brake,

including amain lever, a bell crank fillcrumed thereon-having arable-engaging elerake lever" fut spring connected crumed on said main lever connected tic-said ,brake, a floating lever connected to said brake lever, speed-res onsive means "connect-' latter including a main lever,- means for, limiting the rocking of said mam lever in one directiom a brake lever connected to said, I. brake, a floating lever connected to said brake lever, and speed-responsive means con-- nected to said floating lever fordrawing said main lever a ainst'said limitinggmeans and rocking said l brake. Y

12. The combinatio witharail clamp of:

- controlling means therefor including a-ca ble,7 fa winding drum, a motor for said druni,-a

said floatin' lever for rockin brake, a main ,lever, 'means? for movement thereof in one directiom'a brake lever connected to said brake fulcrumedon. said main lever, a floating lever connectedv to said brakelever, and'means connected to the latter an said brakeever to-"actuate said brake. 13. The combination With a rail clamp of controlling means therefor-including a cable, a wlnd ng drum, a motor for said drum,

' a brake,-a main lever, a'brake Ilever ful- I means and rockin ,crumed thereon, a floating lever connected to said brake lever, stops, and means-com nected to said floating lev'er for drawing I the latter and said mam" lever against said stops and rocking said brakelever on said main lever to applysai'd brake. p

14'. The combination withfa rail clamp of controlling means therefor including a cable, a winding drum, a motor for said drum,.a brake for the latter, amain lever, a: brake lever fulcrumed thereon connected to saidbrake, av floating lever connected to said brakelever, stop means, and means for drawing said floating lever against said. step said brake lever on said main lever to app y said brake. a

15. The combination with a railclamp of a winding drum, a metorfor'said drum, a brake, a support,i.a main lever fulcrumed on said support, a brake lever. connected to'said brake and fulcrumed on-said main lever, a

floating leverconnected to said-brake lever, speed-responsive means and cable-winding limiting means connected to said floating lever and alternatively operable for rocking said floating lever and brake-lever to apply said brake. a h y 16. The combination with a rail clamp'of I controlling means therefor including a cable,

a winding drum connected to said cable, 8,-

rake lever toactuate said ing means connected motor for said drum, a brake for the latter to said brake. and fulcrumed on said main lever, a floating lever connected to said brake lever, stops, cooperating with said main and floating levers, and speed-responsive and cabIe Winding limiting means connected to said floating; lever: v a

. 17. .The combination with a rail clamp of controlling means therefor including a 'cable,

a winding: drum, a motor for the latter, a brake, and controlling means for said brake including a. main lever, cable-engaging 7 means fulcrumed on saidmain lever, a brake "lever connected vto said brake and fulcrumed I on said main lever, a floating lever, alink connecting the latter with said brake lever,

speed-responsive means "connected to one end f saidflOating lever, and cable-winding l1m1t1ng,means connected to the opposite end of'said floating lever;

'18.v The combination with a-rail' clamp of controlling means therefor including a cable,

a winding drum, a motor for said'drum, a

brake,and controlling meansfor said brake f a floatingilever, a link pivotallyconnecting "inc'ludinga' main lever, a support, a link pivt the latter with said brake levenlspeedresponsive m" ns connected to one endof said floating-lever, and cablewinding limitto the opposite end of 'saidfloating lever;

" 19. The combination with ir conveying structure of means to clamp thesame td a.

rail,-a motor for causingsaid structure to travel along sald rail, means lncluding a motor for releasing said clamp means, elec-- trical circuits for said motors, a controller foris'aid circuits, andmeans to prevent said motor circuit. until after. the complet n 0 said clamp motor circuit,

controller-from completing said conveying .20. The combination "with a conveying rail,-means-including, a motor for causing said structure to travel along said rai means including a-motor for releasing said prevent starting said conveyingmotor prior to release of said clainp means by its motor. 21. The combination with a conveying structure ofmeans-to clampjhe same to a .rail, a-motor for said structure, a motorfor releas1ng sa d clamp means, circuits for said motors, a controller for said'c1rcu1ts,'means structure of means to clampthe same to a" controllmg means therefor lncludmgacable,

Ito prgvent completion of said conveyer mo- 1 of said clamp means means cuit prior a) the compasses of ai clamp release motor circuit, and-electromagnetic means forim tomati, ll com pleting said conveyer lmotor, circ -'-ei' release 22. The combination with a conveying structure of a motor for propelling the same along a rail, means to clamp said structure to said ra'il,-1neans for. releasin said clamp including a cable, a windin drum, a motor for said drum; circuits for said-motors, a controller for said circuits, and means for completing said oonveyer motor circuit including a switch in said circuit, an electromagnet and a circuit for the latter for automatically closing said switch after said drum has wound a sufiicient portion of said cable thereon to releasesaid clamp means 23. The combination with a conveying structure of a motor for propelling the same for said circuits having means to prevent 'means ,ucture'of means to clamp along a rail, means to clamp saidstructure to said rail, a motor for releasing said clamp means, a brake for the latter motor, circuits for saidmotors and brake, and a controller starting said 0O11V6y-l II1Ot01-- and applying said brake prior torelease of said'7clamp means by its motor.

245. The combination with a conveying structure of a motor for propellin the same along a rail, means to clamp said structure to said rail, a: motor for releasing said clamp means, a brake for the latter motor, circuits for saidfmotors and brake, a controller for said circuits, and means set in operation by movement of said controller for automatically startin said-conveyer motor and applying-said rake on releaseof said clamp, means by its motor.

25. The combination with a conveying structure of means for clamping the same to a rail, andcontrolli-ng means for said clamp means includinga cable, a drum, a shaft, a switch thereon, a lever on said shaft, a stop, a spring tending to urge said lever against said stop, a trigger for holding said lever in tensioned position, and means actuated from said drum for tripping said trigger to release said lever and shift said switch, or to reset said lever. E

2-6. The combination with a conveying p the same to a rail, and'controlling means for. said clamp fjneans including a'switch, a shaft therefor.

a lever fast on said shaft, :1 stop, spring tending to rock said lever againstsaid stopga trigger to hold said lever away from said stop, and means driven fromlsaid drum, rotative in one direction to trip said trigger, and rotative in the opposite direction to reset sa'd lever.

' rail, and controlling mea s for said clamp 2'7. The combination with -a conveying structure of means to clamp the sameto a' I i a v means includin a. witch and an. o eratinm l .i. D

device for said switch including means for energizing said device and rendering said device effective to shift said switch,:

28. The combination with a conveying structure of means to clamp the same to a rail, and-controlling means for means including two sets of the contar'zts of said sets, and means for shifting said bridge contact with a sharp, quick movement.

said clamp contacts, a bridge contact for alternately connecting 29. The combination with a conveyingstructure of means to clamp the same to a rail, and controlling means for said clamp means including two sets of contacts, a bridge contact for alternately connecting the contacts of said sets, and a device for shifting said bridge contact having provision for 'energizing'and then suddenly rendering the same eiiective, to shift said bridge contact. r

30. The combinationwith, a truck of a casing mounted thereon, jawafor gripping a' rail having arms in sa d casing, togglclmks connecting said jaws, a 'rock'rshaft; j-ournaled in said casing, an arm on said shaft, a rod connecting said. arm with said toggle links, a lever fast on said shaft and a-weight on said lever for' straightening said toggle and causing said jaws to grip the rail.

31; The combination with a truciroi' a, casing mounted thereon, jaws forgripping a rail having arms in said casing, toggle links connecting said jaws, and ineans mounted on said casing connected to said links for on oneofsaid arms tending to press said pin I against an end of said slot.

34. ,The combination'witli.jaws for gripping-a rail,of arms therefor and means for operating said jaws including toggle links and means yielding-iv to transmit movement from. one of said linksto one ofsa-id arm 35. The combination with jaws for gripping a rail. of means for applying or leasing said jaws including toggle links, and means including a spring for transmit ting movement from one ofsaid links a one oflsaid jaws. j

'36.- The combination with jaws for grip ping a rail, segga means, fo applmg or releasing the; same ha prmisibn for compensating for variations in the width '7 of the rail.

37. The combination-with a railclamp of controlling means therefior including a cable 7l,a drum- 85,12, motor 107 for driv ng said drum, 'a brake 1 11, and controlling means .for said brake including a main lever 123',

a brake lever 11'5 'fulcrumed thereon, a floati ing lever 119 connected to said brake lever,

a governor connected to one" end of said floating lever, a solenoid 177 connected to the opposi-teend of said floating lever, and means .127 connected-to said maln'leveri and having an element said table.

38. The-combination with a mil clamp of 4 actuating means for releasing said clamp,i and means including a brake for automati-' cally' arrestin said actuating means on release of said 0 amp. a t

39; The combination with a rail clamp of 1 actuating means for releasing said clamp,

means for releasing said clamps including" and means responsive to the speed of the clamp releasing means and, for c'ontrollin said actuating means.

a 0. In a. traveling bridge, the combination with a plurality of rail clamps, of

cables connected thereto, a motor for haulingin said cables, and means responsive .to

themovement of said cables "for controlling said motor. 5 i 41. The combination with 84 133.11 clamp, of

controlling means therefor including -a weight, a drum, a cable connectin said- .wei'ght and drum, a motor, and; means re,- sponsive to the speed of the caloles for-com trolling the speed of the motor.

42. In a traveling bridge, the combination with a plurality of rail clamps, of cables connected thereto, means tohaul -in and, pay out said .cables to actuate said clamps, and means responsive to slack in said-cables to control clamps. c is r 1 43. The combination with a rail clamp of a cable connected thereto, means to pay, out said cable to 'actuate'said clamp, and means responsive to slack .said cable to control the actuation of said clamp.

44. The combination witharailclampof' wei ht means to apply the same to a rail, 9.

cab e for; actuating said. weight means to release said clamp, -and means'responsive to slack in said cable to check said weight means in applying said clamp. I

45. The combination with a rail clam "of wei htmeans to apply the same to a 13311,; a

cab e connected to said clamp, means to take up said: cable to release said clamp,cmeans automatically to limit the movement of saidii take-up means, and sla'ck and speed-respon- 95% means cooperating with sa d cable to check movement of saidweight means.

operatin 133 for engagement with the actuation of said 46. The combination with a conveying structure of a motor for propelling the same, meansito clamp said structure to a rail, means including a motor for controlling said clamp means, a brake for the latter motor, means for said brake, electrical circuits or'said motors and said brake-operating means, switch means for said circuits,

and means automatically to shift said switch 'meansto break. said clamp motor circuit and ating means circuit on' release. of said clamp means.

48. Thecombination .with a rail clamp of means for -controlling the same-includin a motor,- acircuit for. said motor, a brake or/9 said motor,"operating means for said brake,

acircuit for said operating means, a controller drum hayin'g contact segments there.- on for completing said motor circuit, and

, means for automatically breakin' said motor circuit and completingsaid bra e-operating means circuit on release of said clamp.

49. The combination with .a' conveying structure of a motor forpropellin'g the same along arail, means to clamp the structure to the rail, a motor for controlling said clamp means, circuits forsaid motors, a "controller drum having contact segments thereon for completing said clainp motor circuit and making a portion of the .conv'ey'ing motor circuit, and means for automatically breaking the clamp motor, circuit and completin the conveying motor circuit on :release '0 Said clamp meanfs' v 50. The combination w'th" a -conveying' structure of a motor for propelling the same alonga rail,--and meangv-autom'atica11g acting "as a brake to limit winddriftingnof the structure :insubstantial excess "of a predeterminedjspeed. 5'1.- \The combination with structure ofa motor for propelling the same tially beyond a' predetermined speed- 52. The combination, with; a conveying structure of motor means gfoe pro'pelling the same along a rail, a resistance in shiint with said motor, and a controller for said motor having provision for-completing the circuit along arail, and means including a resistance in shuntwith saidmotor as; "prevent mg wind drifting of thestructuresub'stanthrough saidiresistan'ce when, said controller is setto start said motor.

6 one of said jaws having flange means to sup- 53..Thecombination with a conveying structure of means to clamp the same to a i rail, means to propel said structure along the rail, and controlling nieansior said clamping and propelling means havin pro= vision for arresting and restarting said propelling means prior to clamping the struc ture to the rail.

54. The combination with a conveying structure of means to clamp the same to a rail, means to propel said structure along the rail, and controlling means for said clamping and propelling meanshaving profvision for arresting said propelling means and applying said clamping means, or arresting said propelling means without applying said clamping-means at will.

55. The combination with a conveying structure of means to clampthe same to a rail, means including an' electric circuit to control said clamp means, means 7 including a motor to propel the structure along said rail, an electriccircuit for said motor;

and controliingmeans for said circuits having provision for making or breaking said' motor clrcuit without interrupting said clamp control circuit.

- 56. A rail clamping device comprising a shoe for engagement with a. rail, a cam member for engagement with said shoe having portions ofvarying radius; and means tending to present a shorter radiusjportion of said member opposite said shoe and yieldable to automatically present a longer radius portion opposite said shoe when the device tends to move along the rail;

57, A rail clamping device comprising a shoe'for engagement .with a rail, and means to press said shoe against said rail includ ing a membenhaving 'a tooth connection to. press said shoe against the railv in'cluding'a member out'of contact with the rail adapted to rock relatively to said shoe .au

tomatically to increase its pressure against.

said rail.

58 A rail clamping device comprising a shoe for engagement with a rail, and means with said shoe and adapted to rock relatively thereto to increase its pressure against said rail. 2,1 7

59. A rail clamping devicecomprising a shoe for enga ement with a rail, and means 4 to press said s us against said rail including a member out of contact with the rail having portions of different radius and adapted to rock and automatically increase the pressure of the7shoe against the rail. i

60. A rail clamping deyice comprising opposed jaws, means to draw the same toward said rail, and a protecting shoe for port the shoeo'n said jaw and a tooth for i I interlocking engagement with said jaw.

"61 d rail clampii g device comprising a shogfand a jaw prcgvided with a face for] tween them a portion of the rail, means con- 'trollable by an operator for actuating said clamping devicesto clamp said structure to vthe rail, one of said devices including a movable member and a shoe coiiperating therewith, the movable Y adapted to be displaced by frictional contact of the shoe with the rail when the structure starts to move froma position where it is clamped, said member by its move-' ment serving to press said shoe into-closer gripping engagement with the rail and bringing both said devices into closer grip- I ping relation to the gripped rail portion. I

' 63. A rail clamp device for securing a traveling structure to a rail, comprising 00- operating clamping devices for aclam'ping between them a portion of the rail, one of said devices being provided with? a shoe ,means for placing the shoe in frictiona I contact with the rail, said shoe when applied to the-rail being adapted to be displaced by frictional contact therewithwhen the structure starts to move in either direction; and means on the clamping meansout oftontact withthe rail for moving'tlie 90 shoe into closer frictional contact with. the rail when the structure starts to move in either direction, .said frictionally actuated movement of the shoe serving to bring both said clamping devices into closer gripping relation to the rail. v

r 64;. A rrailclamp device for securing a traveling structure to a rail, comprising opposed clamping jawscarried by saidstructure fand arranged when applied to grip a portion or the rail between them x one of said jaws having a shoe, me'ans for moving said jaw to place said shoe in frictional contact with the rail, said shoe when applied to the rail being adapted'to be displaced by frictional contact therewith when the structure starts to move, automatic f gripp'ing meanson the jaw for iorcing the shoe into closer frictional contact with the rail when the shoe is displaced by movement of the structure, and connections betw'cenrthe 'jaws' to cause such closer frictional contact to'draw said jaws into closer grip iugrela-l tion to the rail; r 65. A rail clamp devicefor a device tendsto move 70.

member being 80 Veling structure. having 1 cooperating- -n embers, 1 means controllable by an operator for clamping betvveenthe n a portion ot the a als o n .01 of said mem er was members with the rail portion.

' sizructure shoe for forcing the shoe into close gripping engagement with the rail. when the clamping structure starts tomove, said increased gripping engagement serving to increase the gripping engagement I of both clamping members with the rail portion. f s

66. A. rail clamp device for a traveling having cooperating members, means controllable by an operator for clamping between them a portion .of the ra1l,.a shoe on one ofsaidmembers, auto-- matic, gripping means out of contact with the rail and cooperating with the shoe for forcing the shoe into close gripping. 'en-. gagement with the rail whenihc clamping structure startsto move, said increasedgripping engagement serving to increase the gripping engagement of both clamping 67. The combination with a v conveyin g structure, of a propelling motor, a rail clamp, means to release the .clamp, including a cable, a vvinding'drumanda motor, a. r -brake to hold the'clamp' released, electromagnetic means for applying the brake, and

,means including .air electromagnetic device for controlling the circuit of the propelling motor and, providing for the closure oil-the latter only after the bra-kehas been applied.

68. The combination with a conveyin structure, of a propelling motor, a ial clamp, a clampreleasing motor, and means including an electromagnetic device for controlling the propelling motor circuit I and providing for. the closure of the latter only after the clamphas been released.

i 69. In a traveling bridge, the'combination with a rail clamp ofia motor.for releasing the clamp, anelectric circuit'for' controlling the clamp, said circuit-being closed when the clamp is released, apropell'ing motor for the bridge, an electric circuit for the propelling motor, a switch for. the propelling motor cir cuit, and electromagnetic means in the clamp control circuit for controllingsaid switch.

70. In a traveling bridge, the "combination with a rail clamp of a Weightfor applying;

said olainp,imeans for lifting said Weight, including a cable, a rope winding drum and a. motor, an electric circuit for holding the p, clamp released, said circuitbeing antomatidaily closed when the clamp-is released, a

a propelling-motor, an electric circuit for the propelling. motor, a switch/for, the' propelling motor I circuit, and' "electromagnetic means in the clamp holding circuit for clos- F ing said switch when the olampholding-cir- Acuitjis closed. l

" ropewindingdrum for simultaneously wind- I v 71; In a traveling the coinbination with a, plurality. ofseparately situated 'wei ht applied rail'clamps, cables connected to lift the weightsand release the clamps, a

ling motor, a clamp controlling circuit, the breaking of which acts to apply the clamp, and provision to prevent the breaking of the clamp controllingcircuit prior to the breaking of the propelling motor circuit.

73.' In a traveling bridge, the combination 'with a 'rail clamp, of a motor to release the 'clamp, ajpropelling motor, a controller for the propelling motor, 7 a clamp controlling circuit, and provision to prevent theicot'ntrol of the 'clamp control-lingcircuit to release the .weight to, apply-the clamp prior to thebreakin of the propelling circuit at the controller.

4. 'A itraveling bridge having a rail clamp, a motor to control the; clamp, a propellin'g motor, electric circuits-for said motors, anda common controllevffor controlling in predetermined order'the several mo tor circuits.

s. 75. A traveling bridge; -a rail 'clamp,a weight for applying said'clamp, a-- motor for'releasing the clamp, a propelling motor, electric circuitsfor said motors and" tohold saidjclamp released, and a common controller for controlling in predetermined" order'said several circuits. l v76. In a traveling bridge, the combination with a plurality" of separately situated rail -clamps, of controlling means therefor in-- "cluding a weight, a'drum, a cable connecting saidfweight and drum, a motor for rotating 1 .thexdruni to take up'the cable and release the 'clamp,'a band brakefor the drum, and elec-' tromagnetic' means. for applying the brake sufficiently to release the clamp.

after thecable has been vvound on the drum 77. The combination with a conveying structure, of a motor for capsingthe same to travelalongia rail, means to clamp said structure to said-rail, means including a- -motor for releasingsaid clamp, and a com 'mon controller for controlliri'g said motors. j 7,8. A traveling bridge clamp, a motor torelease thqblamp, a propelling motor; a controller for the-propelling motor, means'to apply energy g) the clamp-releasing motor, "the stoppa e of ravinga rail which supply serves to apply. the clamp, and

provision for preventing the-stoppage of the clamp-controlling energ'y prior tothe brak -i ing of the propelling motorcircuit.

In testimonyvvhereof, I have name to this specification. 

